Hexin-iii converter is a two-way interface converter between RS-232 and RS-485. It is applied between the main control computer and the single chip microcomputer or peripherals to form a point-to-point, point to multipoint remote multi computer communication network to realize multi computer response communication. It is widely used in industrial automation control system, all-in-one card, access control system, parking lot system, self-service banking system and bus charging system. Canteen food selling system, company employee attendance management system, highway toll station system, etc.

Hexin-iii converter can convert TXD and RXD signals of RS-232 serial port into two-wire balanced half duplex RS-485 signals. There is no need to connect the external power supply. You can steal power directly from the 3-pin of RS-232 port. At the same time, the 7-pin request is sent (RTs), and the 4-pin data terminal is ready (DTR) to supply auxiliary power to hexin-iii. the automatic flow control makes you do not need to reset. The hardware and installation are very simple.

performance parameter

1. Serial port characteristics: the interface is compatible with RS-232C and RS-485 standards of EIA / TIA;

2. Electrical interface: RS-232C end DB9 hole type, connection port, RS-485 port DB9 pin type connection port, with terminal (four position wiring or six position wiring); 3. Working mode: asynchronous half duplex;

4. Transmission medium: ordinary wire, twisted pair or shielded wire; 5. Transmission rate: 300 ~ 11520bps;

6. Transmission distance: 5m (RS-232C end) 1200m (RS-485 end); 7. Communication protocol: transparent;

8. Working environment: – 10 ℃ to 85 ℃, relative humidity 5% to 95%;

9. Signal: RS-232: TXD, RXD, RTs, CTS, DTR, DSR, DCD, GND; RS-485:Date+/Date-,GND;

Wiring and signals

  Detailed explanation of RS232 to RS485 converter

Hexin-iii converter adopts DB9 female connector to connect with RS232 interface, and DB9 male connector at the other end is connected with RS485 interface.

  Detailed explanation of RS232 to RS485 converter

There are two conditions for other working power supplies: supply power directly from RS232 port to pin 3, and supply power to hexin-iii auxiliary power from pins 7 (RTs) and 4 (DTR). When RS232 cannot supply power normally, it can be supplied by db9m6 pin (+ 5V – + 12V) and 5 pin (GND) at RS485 end.

Installation and Application

1. Installation: ① before installing hexin-iii products, prepare two wires (twisted pair);

② Close the serial port of the device (shutdown);

③ The RS232 port of hexin-iii converter is in DCE mode, which can be directly inserted into the db9m serial port of DTE equipment (such as the COM port of computer) and steal power from TXD, DTR and RTS signals. Note that the signal level should be greater than + 5V. If the equipment is in DCE mode, the following connecting lines must be made:

  Detailed explanation of RS232 to RS485 converter

The connection between RS485 equipment and hexin-iii is as follows

  Detailed explanation of RS232 to RS485 converter

2. Apply

1. Communication between RS232 device and RS485 device

This method is mainly applied to the RS232C interface of the equipment at the control end. When the equipment at the controlled end is the RS485 interface, the equipment at both ends cannot be directly connected due to different electrical characteristics. The hexin-iii converter can transparently convert the RS232C interface signal into RS485 signal.

  Detailed explanation of RS232 to RS485 converter

2. RS485 networking application

When an RS232 host wants to control up to 32 RS485 slaves, it can use this method. In order to prevent signal reflection and interference, it is necessary to connect a matching resistance (120 Ω, 1 / 4W) at the terminal of the line.

  Detailed explanation of RS232 to RS485 converter

There are mainly the following two connection modes: ① two hexin-iii connections

HEXIN-III。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。HEXIN-III

Date(+)。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。Date(+)

Date(–)。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。Date(–)

GND。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。GND

② Hexin-iii converter is connected with RS-485 equipment

HEXIN-III。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。 RS485 device

Date(+)。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。T+R+or485+

Date(–)。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。T-R-or485-

GND。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。GND

Fault analysis:

1. Data communication failed

a. Check whether the RS232 interface is connected correctly; b. Check whether the RS485 interface is connected correctly;

c. Check whether the RS232 interface signal level (TXD, DTR, RTs) is lower than + 5V. If it is lower than + 5V, power can be supplied at the 6th pin of db9m; 2. Data loss or garbled code

a. Check whether the data rates at both ends of the data communication equipment are consistent; b. Matching resistance 1 / 4W 120 Ω can be added.

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